Makoto Sakai has championed Sino-Japanese friendship for decades but the past few years are times he would rather forget.

After spending years fostering ties between the two Asian giants, the bilateral relationship took a sudden nosedive in 2001.

The immediate trigger was Japan's decision to approve eight new school textbooks, which critics say gloss over the country's wartime aggression, an issue particularly sensitive in China.

Rows over history books have been just one regular source of tension since the two countries normalised diplomatic ties in 1972. Others include the Diaoyu Islands dispute, contested oil fields in the East China Sea and disagreement over compensation to war victims.

Last year the Japanese watched their national footballers abused and taunted by angry Chinese fans in Beijing at the Asia Cup Final.

Tokyo businessman Makoto Kamikawaji says he was shocked by what he saw on the television.

'How could you expect a football game would lead to such large-scale anti-Japanese riots?' he said.

Meanwhile, mainlanders were infuriated by Japanese Prime Minister Junichiro Koizumi's visit to the Yasukuni Shrine, a memorial dedicated to Japan's war dead, including convicted criminals.

'They'll never repent. They have learned nothing from the war. They are just preparing for a new one,' Shenzhen student Lu Chengtie said.

Anti-Japanese protests broke out in large mainland cities in April. Hundreds of thousands of people took to the streets to vent their anger and some protesters turned violent. Viewers in Japan watched in apprehension as protesters stormed Japanese department stores and attacked some Japanese students. The bitterness not only put off tourists, but also Japanese companies said they would delay investments on the mainland.

But most pressure fell on people such as Mr Sakai, who has been pushing for more social interaction between China and Japan over the past two decades.

'The political environments in China and Japan have changed. Japan is leaning towards the conservative right and China is becoming more nationalistic,' Mr Sakai said.

Shin-ichi Arai, director of a Japanese organisation fighting for compensation for Asian victims of his country's aggressions, said his group's work on the mainland was also affected by the worsening ties.

'Anti-Japanese sentiment in China is high and has made the exchanges much more difficult. Both the quality and quantity of exchanges have dropped,' Professor Arai said.

Times are also tough for liberal politicians in Japan. Tomoko Abe, a legislator from the Social Democratic Party, admitted the calls for reconciliation were waning in both the government and the parliament.

Ms Abe saw the change as the result of a general shift on the global political stage. 'Global politics generally changed towards a more conservative rightist direction after 2000. Mr Koizumi blindly follows the US government's policy. Our foreign policy has been dominated by pro-American voices. It lacks long-term strategy,' she said.

'I don't know if the relationship will improve very soon, but I don't believe it will worsen. The public actually is beginning to realise the importance of good ties with our neighbours. And the voice against Mr Koizumi visiting the Yasukuni Shine is getting stronger,' Ms Abe said.

Mr Sakai agreed. 'The Japanese economic structure has changed. Many people in the business sector understand that we need to maintain a good relationship with China,' he said.

They also agree that more exchanges at the social level will be the key to improving bilateral ties.

'The two governments have each adopted a hardline stance. They have pushed themselves into corners. Now it will be up to the people in both countries to take the first step,' Ms Abe said.

'The most important thing is that people in different countries should have more communication and exchanges. Often hatred is bred by misunderstanding.'

Mr Sakai said Beijing should be more flexible in its Japan policy and reach out to the liberal political camp.

'I hope the Chinese don't just focus on the negative side of Japan. Today the young people in both countries know nothing about each other. This is dangerous,' Mr Sakai said.

'I remember in the 1970s, the Chinese government invited 2,000 Japanese students to visit China. That visit left a long-lasting impression on the students.

'Many of them have now become congressmen and business leaders pushing for better ties. More such visits should be organised.'